The present invention relates to oil well drill bits, and more particularly relates to an improved unitary drill bit having particular utility when drilling in soft to medium unconsolidated formations.
When drilling for oil in soft to medium unconsolidated formations such as those formations found along the Louisiana and Texas Gulf Coast areas of the United States, and in offshore waters of the Gulf of Mexico, "bit balling" is a very common problem. This problem relates to a heavy accumulation of the clay-like unconsolidated formation material around the bit as it rotates through the formation. The formation material actually adheres to the bit rather than flowing away after being cut.
Several patents relate to drill bits used in oil and gas well drilling operations. For example, U.S Pat. No. 2,169,223 to Christian entitled "Drilling Apparatus" relates to a drill bit which is used for flushing fluid into the bore along with the drill. The Christian device uses a flushing fluid that is forced down through the drill stem and passes through openings at the lowermost end portion of the drill bit. Flushing fluid will then return around the drill and the drill stem removing clogging material from the well bore. The Christian devices uses a drill having an axial bore extending from the upper to the lower end of the drill and having an inside seat around the bore. A discharge channel leads downwardly from the bore above the seat and of a tubular barrel shaped to fit through the bore. The Christian device uses two blades which are a fish tail type bit construction. Because of the outwardly extending enlarged fish tail type cutters of Christian, excessive torque can be generated in the drill string. Further, these outwardly extending fish tail type cutters can ball up in unconsolidated type formations known in the industry as "gumbo mud" or like formations.
Another fish tail type bit is the Scott U.S. Pat. No. 1,733,241 entitled "Method of Producing A Hard Surface on Tools and the Like." Scott discusses applying tungsten carbide using an atomic hydrogen torch to generate enough heat to melt the carbide itself. The tungsten carbide in molten condition then forms an alloy with the blade of the cutter according to the Scott patent.
U.S. Pat. No. 2,490,208 issued to H. E. Conklin and entitled "Soft Formation Core Bit Cutter Head" shows a tubular drill bit having outwardly extending cutter blades mounted upon a conically shaped bit which is round in cross-section.
Other patents showing various constructions for drill bits include U.S. Pat. Nos. 2,169,223; 1,887,372; 2,838,284; 2,673,716; and 2,756,023.